Dust trap

The Allende, Murchison, Murray and Orgueil meteorites are particularly highly prized for research into stellar grains, since several kilograms of this material have been identified in each of them. This is sufficient to be able to take samples of the order of 1 g without damaging the source. Such samples can then be subjected to compositional analysis. But how can we extract these stellar jewels, measuring at most 1 /rm in diameter, from the matrix in which they are embedded The best way of finding a needle in a haystack is to bum the hay. Cosmochemists employ basically the same method when they use chemical processes to isolate star dust trapped in meteoritic stone. They may then analyse... 

Cilia Tiny hair-like whips in the bronchi and other respiratory passages that normally aid in the removal of dust trapped on these moist surfaces. 

The open end of the reaction tube is attached to an oil pump through a dust trap, and dry nitrogen is admitted at a rate such that the pressure is maintained at or below 25 mm. The bismuth(III) iodide is sublimed into the receiver end of the tube by heating with the spread burner flame and with an auxiliary Tirrill burner adjusted to maximum heat. Satisfactory progress of the sublimation is indicated by the persistence of yellowish-brown bis-muth(III) iodide vapors and by the absence of the violet color of iodine vapor. When the sublimation is complete, the tube is allowed to cool to room temperature in nitrogen at atmospheric pressure. The product is scraped from the receiver section of the tube and stored out of contact with the atmosphere. The yield is 72% based on bismuth. Anal. Calcd. for Bil3 Bi, 35.44. Found Bi, 35.42. The same result is found upon analysis of a resublimed sample of this product. 

S. G. Libin, in collection Collected Information on Dust Trapping in Non ferrous Metallurgy, Metallurgizdat, Moscow (1959), p. 177. 

Operational Behavior of a Gas Dedusting System. Figure 5.22 shows the technical area of a major plant for the production of water gas from coal. The product gas is freed, to a large degree, of suspended dust particles by means of a dust separator and is transported towards the burner of a gas-fired steam boiler. The dust, via an intermediate dust bin, finally falls into the dust trap. For this purpose, valve (1) remains open most of the time while the installation is operational,... 

Once the dust inside the dust trap reaches a certain level, valve (1) will shut. The dust trap is scoured with nitrogen and the scouring gas is led to... 

This gas dedusting system will not be able to function as designed whenever valve (2), after the dust trap has been emptied, remains open because of a malfunction and the position transmitter (2) reports Valve (2) closed. ... 

Ovenware. Ceramic whiteware or glassware (casseroles etc) of good thermal shock resistance for use in cooking. Overalls. Workers overalls in the pottery industry are designed without lapels, pockets and other dust traps. 

Smock, Potter s Smock, overalls (q.v.) worn by (male) operatives in the pottery industry, which are designed without lapels, pockets and other stitched features which have short sleeves and which are made from the smooth artificial fibre, terylene. They are thus free of dust traps. See also dust, RESPIRABLE dust, HEALTH AND SAFETY. 

Dust traps of such aspect are characterized by presence of the capacity filled with water. Cleared air contacts to this water, and contact conditions are determined by interacting of currents of air and waters. The same interacting calls a water circulation through a zone of a contact at the expense of energy of the most cleared air. 

FIGURE 1 Constructions of scrubbers with inner circulation of a fluid (a) - rotoklon N (USA) (b)- PVM CNII (Russia) (c) - a scrubber a VNIIMT (Russia) (d) - a dust trap to me (Czechoslovakia) (e) - dust trap WNA (Germany) (f) - dust trap Asco (Germany) (g) -dust trap LGP (Russia) (i) - dust trap Klayrator (USA) (k) - dust trap VDN (Austria) (1) - rotoklon RPA a NIIOGAS (Russia). 

Layout of the drip pan in a body of the apparatus which allows to diminish sizes of dust traps to supply their compactness. 

In the scrubbers introduced on Figure 2, and, turn of controlling partitions is made either manually, or is distant with the drive from the electric motor, and in a dust trap on Figure 2, in - manually, moving of partitions rather each other on a threaded connection. In dust traps on Figure 2 (e). The lower partitions are executed in the form of a float or hnked with floats that allow to stabihze clearing process at varying level of a fluid. 

The interesting principle of regiflating is apphed in the dust traps figiued on Figure 1 and Figure 2. In these apparatuses contact devices are had on a wall of the floating chamber entrained in a fliud and hardened in a body by means of joints. Such construe-... 

The process of subdivision of a flitid by a gas flow in the contact charmel of a dust trap occurs at the erqrense of high relative speeds between a flnid and a gas flow. For calculation of average diameter of the drops gained in contact channels, it is expedient to use the empirical formula of the Japanese engineers Nnkiymas and Tanasavas which... 

Autohesion Properties of Some Industrial Dusts and Characteristics of Adhesion in Dust-Trapping Processes... 

The operating efficiency of many gas-purifying systems depends on the nature and particle size of the dust trapped. Very often poor operation of dust traps is due to the fact that no proper allowance has been made for the characteristics of the dusts, especially their particle size and their capacity to stick to each other and to other surfaces, i.e., their autohesion and adhesion. The autohesive and adhesive properties of various dusts have not yet been studied and applied sufficiently. 

S. S. Yankovskii, Dust Trapping and Purification of Gases in Nonferrous Metallurgy, Collection of Scientific Transactions of the Gintsvetmet, No. 20, Metallurgizdat (1963), p. 30. 

A. M. Arslanova, Collection of Information on Dust Trapping in Nonferrous Metallurgy, Metallurgizdat (1957), p. 160. 

---